This invention relates to radio receiving apparatus and more particularly to apparatus for minimizing the interfering effect of a narrow band noise signal superimposed upon the desired signal.
Heretofore, the most common technique for minimizing the interfering signal effect is to reduce the received bandwidth down to that of the desired signal to thereby eliminate adjacent interfering signals. However, this is not effective when the interfering signal is concentrated in the same spectrum segment as the desired signal. Therefore, there exists a need for apparatus to minimize the interfering effect of superimposed narrow band noise.
The present invention adaptively measures the statistics of the interfering noise signal, and by using these statistics together with approximations of the received data signal, generates an interference eliminating function which when multiplied by the combined narrow band noise and data signals tends to reduce the interfering effect of superimposed noise.